The present invention relates to a pneumatic tire for high-speed running, more particularly to an asymmetrical tread pattern capable of improving the high-speed durability without sacrificing the steering stability and wear resistance.
High-performance tires for high-speed running which premise the use on public roads as well as the use in motorsports such as circuit race, Gymkhana and the like, are required to have high rigidity in the tread portion in order to provide good steering stability.
In such high-performance tires, therefore, rib-based tread patterns including a crown rib extending on the tire equator are widely employed.
The crown rib however, tends to generate considerable heat during high-speed running due to relatively higher ground pressure, and there is a possibility that the generated heat is accumulated in the crown rib, and as a results, the rubber of the crown rib causes thermal deterioration, and the high-speed durability of the tire is impaired.
In the case of pneumatic tires for general use, the crown rib may be provided with sipes in order to adjust the rigidity and thereby to reduce the heat generation.
In the case of the above-mentioned high-performance tires, however, if sipes are employed, the steering stability is deteriorated by a deficiency of the rigidity of the crown rib. Further, as the motion of the crown rib during running increases, the wear resistance of the tread portion is deteriorated.